Apparatus for corrugating tubes by fluid pressure



July 8, 1958 P. E. CATE 2,842,182

APPARATUS FOR CORRUGATING TUBES BY FLUID PRESSURE Filed May 2'7, 1955 5 Sheets-Sheet 1 INVENTOR.

Paul E. Cate H18 ATTORNEY.

July 8, 1958 P. E. CATE 2,842,182

APPARATUS FOR CORRUGATING TUBES BY FLUID PRESSURE Filed May 27, 1955 s Sheets-Sheet 2 F/aZ INVENTOR.

Paul E. Cafe BY H18 ATTORNEY.

July 8, 1958 P. E. CATE 2,842,182

APPARATUS FOR CORRUGATING TUBES BY FLUID PRESSURE Filed May 27, 1955 5 Sheets-Sheet 3 *l m E! Q &' IINVENTOR.

Paul E. Cate ms ATTORNEY.

P. E.'CATE July 8, 1958 APPARATUS FOR CORRUGATING TUBES BY FLUID PRESSURE 5 Sheets-Sheet 4 Filed. May 27, 1955 INVENTOR.

- Paul E. Cafe BY WM H1 ATTORNEY.

LI L2 July 8, 1958 APPARATUS FOR CORRUGATING TUBES BY FILUID PRESSURE Filed May 27, 1955 P. CATE 2,842,182

5 aneets-Sheet'S u h i 1: 0

r m 0 E Q 2% m Q INVENTOR.

, Paul E.Cate BY H18 ATTORNEY APPARATUS FOR CQRRUGATIWG TUBES BY FLUID PRESSURE Paul E. Cate, Knoxville, Tenn, assignor to liobertshaw- Fulton Controls Company, Greensbnrg, 3a., corporation of Delaware Application May 27, 1955, Serial No. 511,684

7 Claims. (Cl. 153-73) This invention relates to apparatus for corrugating tubes and more particularly to presses for forming expansible corrugated metallic walls.

Heretofore various devices have been proposed for forming expansible and contractible corrugated metallic walls by spacing forming plates along a metallic tube at regular intervals, thereafter expanding the tube by internal hydraulic pressure until bulges form between adjacent plates, and then forcing the forming plates towards each other to form corrugations in the tube between adjacent plates.

When the tube is thus corrugated, the metallic material of which the tube is formed is subjected to cold working so that the crystalline structure thereof is changed. The manner in which the crystalline structure is modified is dependent upon the rate at which the forming plates are forced together to form the corrugations. With devices of the prior art, wherein a hydraulic cylinder and piston effected closing of the forming plates, it was extremely difiicult if not impossible to control the rate of cold working during formation of the corrugations. It is an object of this invention to control the rate of cold working of the metallic material in a tube during the formation of corrugations therein to thereby control the physical characteristics of the formed tube.

Another object of this invention is to control the rate at which the forming plates of a tube corrugating press are forced together.

In a preferred embodiment of the invention, a ram engages the forming plates and cam means is provided for imparting axial movement to the ram to close the plates and corrugate the tube. The configuration of the cam may be selected to vary the rate of axial movement of the ram and thus control the rate at which the tube is corrugated.

Another object of this invention is to simplify mechanism for corrugating tubes by utilizing a single ram movable initially to position, within the tube, an arbor 2,842,182 Patented July 8, 1958 ice Referring more particularly to the drawings, the press embodying this invention is shown as comprising a machine bed 10 for mounting the several parts of the device and supported by suitable legs 12. Mounted on one end of the bed 10 is a generally rectangular frame 14 which carries a rod 16 extending parallel with the center line of the bed 10. A second rod 18 is also carried by the frame 14 and is positioned parallel to the rod 16 between the frame 14 and the bed 10. A plurality of forming plates 24) are slidably mounted on the rods 16, 18. As shown in Fig. 5 each plate 20 is semicircularly notched at 22 to receive a tube which is to be corrugated as is well known in the art. A plurality of leaf springs 24 are interposed respectively between adjacent plates 20 to normally bias the same into spaced relation with each other and are supported by the rod 16.

A second frame 26 is pivotally mounted on the rod 18 and carries a rod 28 which parallels the rod 18. A plurality of forming plates 30'are slidably mounted on the rod 28 and also engage the rod 18 for pivotal and slidable movement thereon. A plurality of leaf springs 32 carried on the rod 28 and interposed respectively between the plates 30 serve to normally bias the plates 30 into spaced relation relative to each other.

Each of the forming plates 30 is semicircularly notched at 31 and the notch formed therein is adapted to register with the notch 22 formed in each of the plates 20 when the frame 26 is in engagement with the frame 14.

Since the frame 26 is pivotally mounted on the rod 18 it may be swung away from the frame 14 to separate the forming plates 20, 3t) and enable a tube A to be placed therebetween. When the frame 26 is swung back into engagement with the frame 14, the tube A will be positioned within the aligned apertures formed by the registering semicircular notches 22, 31 inthe plates 20, 30, respectively.

Means isprovided for clamping the frame 26 to the frame 14 and is here shown as comprising a latch 34 pivotally mounted at 35 on an extension 37 formed in the frame 26 and engageable with a suitable keeper (not shown) fixed on the frame 14. A manually operable lever 36 is pivotally connected to the bed 10 and is slotted to slidably receive a pin on the free end of extension 37. The connection between the latch 34 and the lever 36 is such that clockwise movement of the lever 36, as viewed in Figs. 1 and 4, will be effective to release the frame 26 and swing the same away from the frame 14, with return movement of the lever 36 being effective to move the through which the tube may be charged with fluid under pressure, the ram being thereafter movable further to collapse the tube.

Other objects and advantages will appear from the following specification taken in connection with the accompanying drawings wherein:

Fig. 1 is a perspective view of a press embodying this invention;

Fig. 2 is a fragmentary elevation of the press shown in Fig. 1;

Fig. 3 is a sectional view taken on the line III-III of Fig. 2;

Fig. 4 is a sectional view taken on the line IV-IV of Fig. 3;

Fig. 5 is a fragmentary sectional view taken on the line V-V of Fig. 2 and shown on a substantially enlarged scale; and

Fig. 6 is a schematic view of a control system for the press shown in Fig. l.

frame 26 into engagement with the frame 14 and latch the frames together.

Mounted on the bed 10 adjacent the frame 14 for lateral slidable movement relative thereto is a carriage 38 which carries a rod 40 extending parallel to the axis of the bed 10. A plurality of spacers 42 are slidably mounted on the rod 40 and are movable with the carriage 38 laterally of the frame 14.

The spacers 42 are elongated in form and are bifurcated at 41 adjacent one end thereof. The bifurcated end 41 of each spacer 42 is adapted to straddle the tube A clamped between the forming plates 20, 30 when the carriage 38 is moved toward the frame 14 to position the spacers 42 between adjacent pairs of forming plates and thus accurately set the axialdistance between the forming plates.

The carriage 38 is biased toward the frame 14 by a helical spring 44 acting between the carriage 38 and a suitable abutment 46 secured to the bed 10. The spring 44 normally acts to hold the spacers 42 in their operative position between the forming plates 20, 30 but means is provided for overcoming the bias thereof and moving the carriage 38 to an inoperative position wherein the spacers 42 are free of the plates 20, 30. This means takes the form of a fluid pressure actuated piston motor 47 mounted on the frame by any suitable means and having an extensible piston 48 engageable with one end of a bell crank lever 50.

The bell crank lever 56 is pivoted on a suitable bracket 52 secured to the bed 10 and is connected at its other end by a link 54 to the carriage 38. Thus, when fluid under pressure is admitted to the motor 47 to extend the piston 48, the bell crank lever is rotated in a counterclockwise direction as viewed in Fig. 4 to move the carriage 38 laterally of the bed 10 against the bias of the spring 44.

Slidably mounted on the bed 10 for reciprocable movement along the center line thereof, is a ram indicated generally by the reference numeral 56. The ram 56 comprises a block 58 slidably mounted on a pair of tracks 60 which are carried by the bed 10. A shaft 62 is threaded into a suitable aperture formed in the block 58 and extends toward the forming plates 20, 38. The

projecting end of the shaft 62 is supported by a bracket 64 which is slidable on a track 66 mounted on the bed 10. The shaft 62 is also journaled in a bearing 68 carried by the frame 14. Since the shaft 62 is threaded into the block 58, it may be rotated to adjust the effective length of the ram 56. However, a lock nut 70 is threaded on the shaft 62 and is engageable with the block 58 to normally prevent rotation of the shaft 62 and lock the shaft and block in a selected relation to each other.

As shown in Fig. 5, the end of the shaft 62 adjacent the forming plates 20, 30 is provided with a sealing head 72. The sealing head 72 comprises a casing 74 threaded on the end of the shaft 62 and having a recess 76 formed in the opposite face thereof. The open end of the recess 76 is closed by a plate 78 which is is secured to the casing 74 by a plurality of screws 80 and which carries on its outer face an axially extending arbor 32 adapted to be received in the tube A which is to be corrugated. The inner face of the plate 78 also carries an arbor 84 which extends into the recess 76 and engages the bottom wall thereof while being spaced from the side wall. Slidably mounted on the arbor 84 and operative between the side wall of the recess 76 and the arbor 84 is an annular piston 86 which is biased toward the bottom wall of the recess 76 by a spring 88.

The piston 86 is provided with an annular cam surface in the form of a beveled edge 90 for imparting radial movement to a clamping element. The clamping element comprises a split ring 92 loosely mounted in an annular groove 94 formed on the casing 74 and having a plurality, in this instance four, of radially inwardly extending portions 96. The portions 96 of the ring 92 are beveled at their inner ends and extend through suitable apertures formed in the casing 74 to be engageable by the t cam surface 90 on the annular piston 86.

Means is provided for admitting fluid under pressure to the recess 76 between the bottom wall thereof and the adjacent end of the annular piston 86 for moving the latter into engagement with the portions 96 of the ring 92 to effect radial expansion of the ring 92. To this end, a conduit 98, which is adapted to be connected to a source of fluid under pressure, is connected to the casing 74 to communicate with a bore 100 formed in the casing 74 and communicating with a passage 102 which opens into 3 the recess 76 between the arbor 84 and the side wall of the recess 76. The bore 100 also communicates with a passage 104 which extends axially through the arbors 82, 84. Thus fluid under pressure admitted tto the easing 74 through the conduit 98 will not only flow into the recess 76 to actuate the annular piston 86, but will also flow through the passage 104 into the interior of the tube A supported on the arbor 82 and the forming plates 20, 30.

The first pair of cooperating forming plates 20, 30 immediately adjacent the sealing head 78 is provided with an annular recessed collar 106 adapted to encompass the end of the sealing head 72 and provided with a radially extending flange 108 adapted to abut the plate 78 of the sealing head. It will be understood that the annular collar 106 and the flange 108 are each formed in two semicircular halves, the halves being mounted respectively on the plates 20, 30.

As shown in Fig. 2, the ram 56 is biased away from the forming p ates 20, 30 by a spiral spring 112 anchored at its outer end to the frame 10 and secured at its inner end to a shaft 114 journalled to the tracks 60. A pinion 116 is carried on that portion of the shaft 114 disposed between the tracks 60 and meshes with a rack 118 secured to the underside of the block 58. Movement of the ram 56 toward the forming plates 26, 30 thus serves to rotate the pinion 116 and wind the spiral spring 112 which is effective to move the ram 56 away from the forming plates 20, 30 when it unwinds.

The block 53 is provided with a pair of cam followers in form of a first roller 120 pivotally mounted on the block 53 and a second roller 122 rotatably mounted in a bracket 124 which is slidably mounted on the block 58. The bracket 124 is adaptde to be adjusted longitudinally of the block 58 by means of an adjusting screw 126 which extends into engagement with the bracket 124 and is threaded through a support 127 carried by the block 58.

Engageable with the roller 120 on the block 58 is a wiper cam 123 which is keyed to a cam shaft to rotate therewith. The cam 128 is provided with a hub 132, see Fig. 2, having a serrated end face engageable with a serrated end face of a hub 134 formed on a second wiper cam 136 in turn mounted on the cam shaft 130 immediately adjacent the cam 128. The cam 136 engages the roller 122 and is held in fixed relation with the cam 128 by a nut 138 which is threaded on the end of the cam shaft 136 and engages the cam 136 to force the serrated hub 134 into engagement with the serrated hub 132. It will be apparent that the angular position of the cam 136 relative to the cam 128 may be adjusted simply by loosening the nut 138, rotating the cam 136 on the cam shaft 130, and then retightening the nut 138 to force the serrated hubs 132, 134 together.

The cam shaft 130 is mounted on the bed 10 in a pair of pillow block bearings 140 and is connected, at the end opposite the end which carries the cams 128, 136, to the output shaft of a reduction gear 142. The reduction gear 142 is driven by an electric motor 144 through a suitable belt 146.

The cam 128 is here shown as having a substantially spiral-shaped cam surface which, when in engagement with the roller 120, will impart uniform slidable movement to the ram 56 upon uniform rotation of the cam shaft 130. However, it will be apparent that the configuration of the cam 128 may be varied to vary the rate of movement of the ram 56 during certain portions of the stroke to thereby control the rate at which the tube is collapsed and thus control the rate of cold working.

The leading edge of the cam 136, which is shown in engagement with the roller 122 in Fig. 3, is of generally spiral form but terminates in a surface which is circular in form with all points thereof equidistant from the center of the cam shaft 139. Thus, upon rotation of the cams 128, 136 in a clockwise direction as viewed in Fig. 3, the follower 122 will ride up the spiral portion of the cam element 136 to impart axial movement to the ram 56, such movement being sufiicient to move the arbor 82 into a tube supported in the forming plates 20, 30. As the follower 122 rides up onto the circular portion of the cam 136, axial movement of the ram 56 terminates although the cam 136 may continue to rotate. As the cams 136, 128 rotate, the spiral surface of the cam 128 moves into engagement with the follower 120 to impart additional axial movement to the ram 56 for collapsing asaaisa cams 136, 128 are so adjusted, the period of revolution of the circular surface of the cam 136 represents the dwell during which controls, to be described hereinafter, are actuated to permit charging of the tube to be corrugated with fluid under pressure to cause bulging of the tube between adjacent forming plates 20, 30 prior to formation of the bellows and collapsing of the forming plates 20, 30.

The cam shaft 130 also carries a pair of cams 148, 150 which are respectively associated with a valve 152 and a cooperative cam follower 149 and a switch 154 and a cooperative cam follower 151. The function of the valve 152 and switch 154 will be more fully brought out together with the remaining portions of the control system shown in Fig. 6 in a description of the operation of the apparatus which follows.

To operate the disclosed embodiment of the invention, the operator unlatches the frame 26 and swings the same about the rod 18 to separate the forming plates 30 from the forming plates 20. Asuitable metallic tube A having one closed end is then placed in the semicircular recesses of the forming plates 20 with the closed end abutting the end of the frame 14. With the tube A in place, the frame 26 is returned to its initial position and clamped by the latch 34. When the frame 26 is thus latched, the forming plates 30 coact with the forming plates 20 to encompass the tube A.

As the frame 26 moves to its clamped position, it engages a switch 158 carried on the frame 14 to complete an energizing circuit for the motor 144 which may be traced as follows: From a line wire L1, wire 160, switch 158, wire 162, motor 144, wire 164, normally closed switch 154, wire 165, to line wire L2.

When the motor 144 is energized, it is operative to drive the cam shaft 130 through the belt 146 and reduction gear 142. Rotation of the cam shaft 130 will rotate the cams as carried thereby and, since earn 136 is in engagement with the follower 122, such rotation will cause the cam 136 to move the ram 56 to the right as viewed in the drawings until the arbor 82 is positioned within the tube A. Preferably, the axial location of the follower 122 relative to the ram 56 is accurately adjusted with the adjusting screw 126 to position the plate 78 of the sealing head 72 immediately adjacent the open end of the tube A when the circular portion of the earn 136 is in engagement with the follower 122. Thus, axial movement of the ram 56 terminates when the arbor 82 is positioned within the tube A and the follower 122 is riding along the circular portion of the cam 136.

The cam 148 is positioned on the cam shaft 130 to open the valve 152 after the follower 122 moves onto the circular portion of the cam 136. When the valve 152 is opened, the sealing head '72 is connected to a source of fluid under pressure, here shown as an air actuated pressure differential pump 166 which is supplied with air under pressure through a conduit 168 and with a suitable liquid such as water through a conduit 170. Liquid under relatively high pressure is conducted from the pump 166 to the sealing head 72 through a conduit 172 communicating with the pump 166, through the valve 152, a conduit 174, manually operable valve 176 and conduit 98 to the sealing head 72.

Admission of high pressure fluid to the sealing head 72 causes the piston 86 to actuate the split ring clamping element 92 causing the same to clamp the sealing head to the collar 106 carried by the first pair of forming plates 20, 30. Fluid under pressure is also admitted through the passage 104 in the arb'ors 82, 84 to the interior of the tube A where it acts to form bulges in the tube between the pairs of forming plates 20, 30 in a manner well known in the art.

The cam 150 is positioned on the cam shaft 130 to open the switch 154 immediately after the cam 148 opens the valve 152. Opening of the switch 154 breaks the hereinbefore traced energizing circuit for the motor 144 and rotation of the cam shaft 130 is terminated. Since valve 152 remains open until the cam 148 is again rotated into actuating position, fluid pressure from the pump 1-66 is maintained in tube A during the complete operating cycle.

An O-ring seal in the arbor 82 operates to seal the open end of tube A in the sealing head 72 while the closed end of tube A abuts the end of frames 14 and 26.

As fluid pressure builds up in the tube A, it also builds up in the conduit 98. When the pressure in the conduit 98 reaches a value suflicient to bulge the tube A, it causes a normally open fluid pressure actuated switch 180 to close. Closing of the switch 180 completes an energizing circuit for a solenoid valve 184 which controls admissionof fluid under pressure to the fluid pressure operated motor 47. This energizing circuit may be traced as follows: From line wire L1 through wire 186, solenoid winding of solenoid valve 184, wire 188, switch 180 and wire to line wire L2.

When the solenoid valve 184 is energized, it opens to admit water under pressure from the conduit 170 through a conduit 192 to the motor 47 thereby extending the piston 48 and pivoting the bell crank lever 50 to move the carriage 38 to the left as viewed in Fig. 4. Such movement of the carriage 38 will move the spacers 42 from between the forming plates 20, 30.

As the carriage 38 moves to its limiting position, it engages a switch 194 to complete a second energizing circuit for the motor 144 which may be traced as follows: From line wire L1 through wire 160, switch 158, wire 162, motor 144, wire 164, wire 196, switch 194, wire 200, a normally closed switch 198, wire 202, to line wire L2.

Energization of the motor 144 causes resumption of rotation of the cam shaft to move the cam 128 into engagement with the follower 120, further rotation of the earn 128 being effective to move the ram 56 to the right as viewed in the drawings thereby collapsing the tube A in a manner well known in the art.

After the completion of the operation, the follower 120 drops off the spiral surface of the cam 128 to permit the ram 56 to be returned to its initial position under the bias of the spring 112. Such return movement of the ram 56 and the block 58 being effective to move a suitable abutment 204 adjustably secured to the block 58 into engagement with the normally closed switch 198 to open the same and break the hereinbefore traced energized circuit for the motor 144.

Preferably return movement of the ram 56 is delayed through operation of a suitable damping mechanism indicated generally by the reference numeral 206 which may be of the type well known in the art. A damping rod 207, associated with the mechanism 206, is connected to the bracket 64 and serves to dampen the relatively fast return of the ram 56 under action of the spring 112.

When the ram 56 reaches the end of the stroke, the cam 148 is effective to actuate the valve 152 to connect the interiorv of the tube A with a drain to thereby release the sealing head '72 and permit return movement of the cam 56.

Although a single embodiment of the invention has been shown and described, it will be apparent to those skilled in the art that various changes in details of construction and arrangement of parts may be made without departing from the scope of the invention as defined'in the appended claims.

It is claimed and desired to secure by Letters Patent:

1. In a device for corrugating tubes having a plurality of pairs of cooperating forming plates, :1 frame in which corresponding plates of said pairs are slidably mounted. means for moving at least one of each of said pairs of plates to clamp a tube between cooperating plates, and a ram for collapsing the tube axially, the combination of an arbor movable with said ram and adapted to be received within the tube, means for supplying fluid under pressure to the interior of the tube through said arbor to bulge the tube between said plates, cam follower means on said arms, rotatable cam means cooperable with said follower means for imparting axial movement thereto, motor means for rotating said cam means, said cam means having a first surface cooperable with said follower means for moving said ram to a position wherein said arbor is disposed within the tube, a second surface cooperable with said follower means for maintaining said ram in said position for a predetermined period, and a third surface for moving said ram axially to collapse the tube.

2. A device for corrugating tubes as claimed in claim 1 wherein said cam means includes a cam shaft, a first cam on said shaft and having said first and second surfaces formed thereof, a second cam on said shaft and having said third surface formed thereon, and means for adjusting the angular relation between said cams.

3. In a device for corrugating tubes having a plurality of pairs of cooperating forming plates, a frame in which corresponding plates of said pairs are slidably mounted, means for moving at least one of each of said pairs of plates to clamp a tube between cooperating plates, and a ram for collapsing the tube axially, the combination of an arbor on said ram and adapted to be received in the open end of the tube, means for admitting fluid under pressure through said arbor to the interior of the tube, clamping means for establishing an operative connection between said arbor and one pair of said plates, and fluid operator means encompassing said arbor for actuating said clamping means.

4. In a device for corrugating tubes having a plurality of pairs of cooperating forming plates, a frame in which corresponding plates of said pairs are slidably mounted, means for rotating at least one of each of said pairs of plates to clamp a tube between cooperating plates, and

a ram for collapsing the tube axially, the combination of V a sealing head on said ram, an arbor projecting from said sealing head and adapted to be received in the open I) end of the tube, means for admitting fluid under pressure through said arbor to the interior of the tube, abutment means on one pair of said plates and adapted to encompass said sealing head, at least one radially movable element in said head engageable with said abutment means for clamping said head to said one pair of plates, and an axially movable, fluid pressure operated piston in said head for actuating said element.

5. A device for corrugating tubes as claimed in claim 3 and including means for imparting limited axial movement to said ram to position said arbor within said tube, and means for imparting additional axial movement to said rain to collapse the tube after said head is clamped to said one pair of plates.

6. In device for corrugating tubes having a plurality of pairs of cooperating forming plates, a frame in which corresponding plates of said pairs are slidably mounted, means for moving at least one of each of said pairs of plates to clamp a tube between cooperating plates, and a ram for collapsing the tube axially, the combination of an arbor movable with said ram and adapted to be received within said tube, means for supplying fluid under pressure to the interior of said tube through said arbor to bulge said tube between said plate, a pair of cam followers on said ram, means for adjusting at least one of said followers axially of said ram, a rotatable cam shaft, a first cam on said cam shaft, said first cam having a surface coopereble with one of said followers for moving said ram to a position wherein said arbor is disposed within the tube and a second surface cooperable with said one follower for maintaining said ram on said position, a second cam on said cam shaft and having a surface cooperable with the other of said followers for moving said ram axially to collapse the tube.

7. A device for corrugating tubes as claimed in claim 6 wherein means is provided for adjusting the angular relation between said cams.

References Cited in the file of this patent UNITED STATES PATENTS 1,689,620 Clifford Oct. 30, 1928 1,865,678 Clifford July 5, 1932 1,980,264 Giesler Nov. 13, 1934 2,217,799 Giesler Oct. 15, 1940 2,610,667 Puster Sept. 16, 1952 FOREIGN PATENTS 650,333 Great Britain Feb. 21, 1951 

